The HTC First, running Chat Heads, one of the features of Facebook Home. / Facebook

by Scott Martin, USA TODAY, @scottysmartin

by Scott Martin, USA TODAY, @scottysmartin

MENLO PARK, Calif. - Facebook today unveiled its long-rumored mobile phone foray, in a grab for greater mobile ad dollars that puts the social network's services front and center on the home screen.

The social giant unveiled an Android download that can transform mobile phones to feature on home screens its family of Facebook apps, without clicking into apps, along with a phone coming from HTC.

"You're going to be able to turn your Android phone into a great social phone," Facebook CEO Mark Zuckerberg said at a press conference at the company's headquarters here. "We're calling this Home."

Facebook will launch with HTC a phone called the First, which will run on AT&T and is now available for preorder at $99.99 to ship April 12. People using phones powered by Android will be able to download the Facebook Home look on that date.

"You have a great Facebook experience," says Ralph de la Vega, president and CEO of AT&T Mobility, who discussed the AT&T partnership.

Deeper hooks into mobile phones could land more mobile advertising revenue for Facebook, a key area of growth as users increasingly come from mobile.

What Facebook is doing is creating what it calls "Cover Feed" on the home screen of mobile phones that allows people to immediately swipe into Facebook updates and double-click to "like" items or begin commenting. The move also gives messaging more attention with what Facebook calls "Chat Heads" - friends' mug shots that instantly appear on the home screen for the user to engage with at a tap or dismiss with a swipe.

Facebook is expected to make $1.5 billion from mobile advertising this year, according to researcher eMarketer. That's up from $471 million last year. The research firm forecasts the social network will haul in $2.7 billion in mobile ad revenue in 2014.

"It is a necessity to be more visible to the consumer," says Gartner analyst Carolina Milanesi.

Facebook's move kicks Google from center stage on mobile phones with Home. "This does put Facebook on top of what was a Google-branded experience. Now to get to Google you're effectively a couple of clicks down," says analyst Greg Sterling.

Facebook's current mobile app features Local Search, something Sterling expects would bubble to the surface to eventually reside on the home screen. "If they bring Local Search into Home there are some pretty big implications for Google, for Google Search and Maps," says Sterling.

"I suspect they will get some substantial number of people -- they have a billion members --- to download the app on Android," Sterling points out.

Facebook is planning to launch Home on tablets in several months. The new Facebook experience will not be available for Apple's iOS devices.

The Android launch from Facebook comes as speculation mounts for a summer release of another iPhone. Not to mention, Samsung's Galaxy S4 is expected to be available around the end of the month, and HTC's One is slated for this month amid a wave of consumer options including BlackBerry's Q10, expected this month or next.

Facebook's download will first work on the HTC One X, HTC One X+, Samsung Galaxy S3 and Galaxy Note 2 as well as the HTC First. The Home download will also be available on the upcoming Galaxy S4 and HTC One. More devices will follow.

"It's all about connecting with other people," says HTC CEO Peter Chou. "It's a great opportunity to bring mobile and social together."